I. Field of the Invention
This invention relates generally to metal working machines, and more particularly to a portable boring bar assembly with a radial feed head that can be used to rebore cylindrical apertures and/or to reface flange surfaces such as may be found on valves and other pipe or casing fittings in the field.
II. Discussion of the Prior Art
Portable boring bars are well known in the art. They generally consist of an elongated, cylindrical bar having a tool bit mounted thereon where the cylindrical bar is journaled for rotation in a frame attachable to the workpiece. A first drive member rotates the bar and a second drive member provides axial feed to the bar and the first drive member. This general construction can be recognized in several patents including the York U.S. Pat. No. 4,932,814, the Flaten U.S. Pat. No. 4,573,837 and the Sverdlin U.S. Pat. No. 4,652,186.
For example, in the York '814 patent, there is described an arrangement in which a cylindrical boring bar is journaled for rotation in a pair of supports and is adapted to translate the boring bar and its rotary drive motor assembly. A boring tool is mounted along the length of the boring bar and projects radially there from for engaging the wall of a cylindrical bore to be refurbished.
The Ricci et al. U.S. Pat. No. 6,447,220 B1 improved upon these by providing a much more facile machine where the mechanism for rotating the boring bar as well as the drive for translating the cutting head can be adjustably positioned anywhere along the length of the boring bar. While this was a remarkable improvement in terms of adjustability, simplification of alignment, available torque, radial displacement, and feed rate control, this design still required two separate and distinct drive members to accomplish radial and axial movement of the cutting head.
The present invention is advantageous over the prior art due to new concepts included in its simplified and scaled-back design. Some differences include a single drive member operating a feed screw that runs down the bore bar enabling both radial and axial feed of the head as well as an improved facing head design. The head has an actuating shaft that allows it to stop and feed radially using the same feed screw used for axial feed. Because this design creates an effective tool that can be adjusted radially and axially using a single drive member, there is a substantial increase in efficiency and reduction in the required cost.